Mercury Clathration-Driven Phase Transition in a Luminescent Bipyrazolate Metal−Organic Framework: A Multitechnique Investigation

Mercury is one of the most toxic heavy metals. By virtue of its triple bond, the novel ligand 1,2-bis(1H-pyrazol-4- yl)ethyne (H2BPE) was expressly designed and synthesized to devise metal−organic frameworks (MOFs) exhibiting high chemical affinity for mercury. Two MOFs, Zn(BPE) and Zn(BPE)·nDMF [interpenetrated i-Zn and noninterpenetrated ni-Zn·S, respectively; DMF = dimethylformamide], were isolated as microcrystalline powders. While i-Zn is stable in water for at least 15 days, its suspension in HgCl2 aqueous solutions prompts its conversion into HgCl2@ni-Zn. A multitechnique approach allowed us to shed light onto the observed HgCl2-triggered i-Zn-to- HgCl2@ni-Zn transformation at the molecular level. Density functional theory calculations on model systems suggested that HgCl2 interacts via the mercury atom with the carbon−carbon triple bond exclusively in ni-Zn. Powder X-ray diffraction enabled us to quantify the extent of the i-Zn-to-HgCl2@ni-Zn transition in 100−5000 ppm HgCl2 (aq) solutions, while X-ray fluorescence and inductively coupled plasma-mass spectrometry allowed us to demonstrate that HgCl2 is quantitatively sequestered from the aqueous phase. Irradiating at 365 nm, an intense fluorescence is observed at 470 nm for ni-Zn·S, which is partially quenched for i-Zn. This spectral benchmark was exploited to monitor in real time the i-Zn-to-HgCl2@ni-Zn conversion kinetics at different HgCl2 (aq) concentrations. A sizeable fluorescence increase was observed, within a 1 h time lapse, even at a concentration of 5 ppb. Overall, this comprehensive investigation unraveled an intriguing molecular mechanism, featuring the disaggregation of a water-stable MOF in the presence of HgCl2 and the self-assembly of a different crystalline phase around the pollutant, which is sequestered and simultaneously quantified by means of a luminescence change. Such a case study might open the way to new-conception strategies to achieve real-time sensing of mercury-containing pollutants in wastewaters and, eventually, pursue their straightforward and costeffective purification.University of Insubria for partial fundingPrograma Juan de la Cierva Formación (FJC2020-045043-I)MCIN/AEI/10.13039/501100011033European Union NextGenerationEU/PRTR (Grants PID2020- 113608RB-I00 and TED2021-129886B-C41

The Tidal Evolution of Local Group Dwarf Spheroidals

(Abridged) We use N-body simulations to study the evolution of dwarf spheroidal galaxies (dSphs) driven by galactic tides. We adopt a cosmologically-motivated model where dSphs are approximated by a King model embedded within an NFW halo. We find that these NFW-embedded King models are extraordinarily resilient to tides; the stellar density profile still resembles a King model even after losing more than 99% of the stars. As tides strip the galaxy, the stellar luminosity, velocity dispersion, central surface brightness, and core radius decrease monotonically. Remarkably, we find that the evolution of these parameters is solely controlled by the total amount of mass lost from within the luminous radius. Of all parameters, the core radius is the least affected: after losing 99% of the stars, R_c decreases by just a factor of ~2. Interestingly, tides tend to make dSphs more dark-matter dominated because the tightly bound central dark matter ``cusp'' is more resilient to disruption than the ``cored'' King profile. We examine whether the extremely large M/L ratios of the newly-discovered ultra-faint dSphs might have been caused by tidal stripping of once brighter systems. Although dSph tidal evolutionary tracks parallel the observed scaling relations in the luminosity-radius plane, they predict too steep a change in velocity dispersion compared with the observational estimates hitherto reported in the literature. The ultra-faint dwarfs are thus unlikely to be the tidal remnants of systems like Fornax, Draco, or Sagittarius. Despite spanning four decades in luminosity, dSphs appear to inhabit halos of comparable peak circular velocity, lending support to scenarios that envision dwarf spheroidals as able to form only in halos above a certain mass threshold.Comment: 17 pages, 12 figs., accepted by Ap

An amplifier-less acquisition chain for power measurements in series resonant inverters

Successive approximation register (SAR) analog-to-digital converter (ADC) manufacturers recommend the use of a driver amplifier to achieve the best performance. When a driver amplifier is not used, the conversion speed is severely penalized because of the need to meet the settling time constraint. This paper proposes a simple digital correction method to raise the performance (conversion speed and/or accuracy) when the acquisition chain lacks a driver amplifier. It is intended to reduce the cost, size and power consumption of the conditioning circuit while maintaining acceptable performance. The method is applied to the measurement of the output power delivered by a series resonant inverter for domestic induction heating

La construcción del “derecho a la ciudad” desde las comunas de la Ciudad Autónoma de Buenos Aires

El objetivo de la ponencia es contextuar la temática de las comunas porteñas en el marco del Derecho a la Ciudad y mostrar cómo el desarrollo de las mismas exhibe claroscuros que señalan inéditas potencialidades, debilidades y oportunidades de la democracia participativa, propiciante del despliegue de capacidades políticas responsables, pensantes y creativas en la población. La metodología utilizada se basa en un análisis histórico del surgimiento de las comunas porteñas junto a una breve reseña y análisis de diversos aspectos particulares destacables de las Comunas 9, 14 y 15. En calidad de miembros de dichos Consultivos Comunales, los autores hemos sido (y seguimos siendo) actores de sendas experiencias políticas que nos revitalizan y las que entendemos son inéditos intentos para dotar a la devaluada democracia contemporánea de una mayor densidad política, social, ambiental y humana. Del contrapunto entre las tres diferentes experiencias señaladas se extraen conclusiones acerca del estado de situación de la democracia participativa en las comunas de Buenos Aires.The paper’s purpose is to focalize into the existence of the Buenos Aires’ comunes within the context of the Right for the City and to show the bright and dark sides of their development as indicators of participatory democracy strengths, weaknesses and opportunities, all of which fosters the development of responsable, thinkable and creative political capacities of the population. The methods used are an historical analysis of Buenos Aires communes’ origins and a brief note and analysis about the particular notable aspects related to Comunes 9, 14 and 15. As members of the Consultative Councils of those communes we, the authors, have been (and nowadays are) actors within these political experiences which revitalize us and which we look at as innovative attempts for attaining a new democracy politically, socially and humanly replenished. At the end, from a side-to-side comparison of the three diverse experiences, we draw conclusions about the participatory democracy’ situation in the communes of Buenos Aires.Eje 3: Derecho a la ciudad: mutaciones, recomposiciones, adaptaciones, reformulaciones.Facultad de Arquitectura y Urbanism

Design & Optimization of Large Cylindrical Radomes with Subcell and Non-Orthogonal FDTD Meshes Combined with Genetic Algorithms

The word radome is a contraction of radar and dome. The function of radomes is to protect antennas from atmospheric agents. Radomes are closed structures that protect the antennas from environmental factors such as wind, rain, ice, sand, and ultraviolet rays, among others. The radomes are passive structures that introduce return losses, and whose proper design would relax the requirement of complex front-end elements such as amplifiers. The radome consists mostly in a thin dielectric curved shape cover and sometimes needs to be tuned using metal inserts to cancel the capacitive performance of the dielectric. Radomes are in the near field region of the antennas and a full wave analysis of the antenna with the radome is the best approach to analyze its performance. A major numerical problem is the full wave modeling of a large radome-antenna-array system, as optimization of the radome parameters minimize return losses. In the present work, the finite difference time domain (FDTD) combined with a genetic algorithm is used to find the optimal radome for a large radome-antenna-array system. FDTD uses general curvilinear coordinates and sub-cell features as a thin dielectric slab approach and a thin wire approach. Both approximations are generally required if a problem of practical electrical size is to be solved using a manageable number of cells and time steps in FDTD inside a repetitive optimization loop. These approaches are used in the full wave analysis of a large array of crossed dipoles covered with a thin and cylindrical dielectric radome. The radome dielectric has a thickness of ~λ/10 at its central operating frequency. To reduce return loss a thin helical wire is introduced in the radome, whose diameter is ~0.0017λ and the spacing between each turn is ~0.3λ. The genetic algorithm was implemented to find the best parameters to minimize return losses. The inclusion of a helical wire reduces return losses by ~10 dB, however some minor changes of radiation pattern could distort the performance of the whole radome-array-antenna system. A further analysis shows that desired specifications of the system are preserved

La construcción del “derecho a la ciudad” desde las comunas de la Ciudad Autónoma de Buenos Aires

El objetivo de la ponencia es contextuar la temática de las comunas porteñas en el marco del Derecho a la Ciudad y mostrar cómo el desarrollo de las mismas exhibe claroscuros que señalan inéditas potencialidades, debilidades y oportunidades de la democracia participativa, propiciante del despliegue de capacidades políticas responsables, pensantes y creativas en la población. La metodología utilizada se basa en un análisis histórico del surgimiento de las comunas porteñas junto a una breve reseña y análisis de diversos aspectos particulares destacables de las Comunas 9, 14 y 15. En calidad de miembros de dichos Consultivos Comunales, los autores hemos sido (y seguimos siendo) actores de sendas experiencias políticas que nos revitalizan y las que entendemos son inéditos intentos para dotar a la devaluada democracia contemporánea de una mayor densidad política, social, ambiental y humana. Del contrapunto entre las tres diferentes experiencias señaladas se extraen conclusiones acerca del estado de situación de la democracia participativa en las comunas de Buenos Aires.The paper’s purpose is to focalize into the existence of the Buenos Aires’ comunes within the context of the Right for the City and to show the bright and dark sides of their development as indicators of participatory democracy strengths, weaknesses and opportunities, all of which fosters the development of responsable, thinkable and creative political capacities of the population. The methods used are an historical analysis of Buenos Aires communes’ origins and a brief note and analysis about the particular notable aspects related to Comunes 9, 14 and 15. As members of the Consultative Councils of those communes we, the authors, have been (and nowadays are) actors within these political experiences which revitalize us and which we look at as innovative attempts for attaining a new democracy politically, socially and humanly replenished. At the end, from a side-to-side comparison of the three diverse experiences, we draw conclusions about the participatory democracy’ situation in the communes of Buenos Aires.Eje 3: Derecho a la ciudad: mutaciones, recomposiciones, adaptaciones, reformulaciones.Facultad de Arquitectura y Urbanism

La construcción del “derecho a la ciudad” desde las comunas de la Ciudad Autónoma de Buenos Aires

El objetivo de la ponencia es contextuar la temática de las comunas porteñas en el marco del Derecho a la Ciudad y mostrar cómo el desarrollo de las mismas exhibe claroscuros que señalan inéditas potencialidades, debilidades y oportunidades de la democracia participativa, propiciante del despliegue de capacidades políticas responsables, pensantes y creativas en la población. La metodología utilizada se basa en un análisis histórico del surgimiento de las comunas porteñas junto a una breve reseña y análisis de diversos aspectos particulares destacables de las Comunas 9, 14 y 15. En calidad de miembros de dichos Consultivos Comunales, los autores hemos sido (y seguimos siendo) actores de sendas experiencias políticas que nos revitalizan y las que entendemos son inéditos intentos para dotar a la devaluada democracia contemporánea de una mayor densidad política, social, ambiental y humana. Del contrapunto entre las tres diferentes experiencias señaladas se extraen conclusiones acerca del estado de situación de la democracia participativa en las comunas de Buenos Aires.The paper’s purpose is to focalize into the existence of the Buenos Aires’ comunes within the context of the Right for the City and to show the bright and dark sides of their development as indicators of participatory democracy strengths, weaknesses and opportunities, all of which fosters the development of responsable, thinkable and creative political capacities of the population. The methods used are an historical analysis of Buenos Aires communes’ origins and a brief note and analysis about the particular notable aspects related to Comunes 9, 14 and 15. As members of the Consultative Councils of those communes we, the authors, have been (and nowadays are) actors within these political experiences which revitalize us and which we look at as innovative attempts for attaining a new democracy politically, socially and humanly replenished. At the end, from a side-to-side comparison of the three diverse experiences, we draw conclusions about the participatory democracy’ situation in the communes of Buenos Aires.Eje 3: Derecho a la ciudad: mutaciones, recomposiciones, adaptaciones, reformulaciones.Facultad de Arquitectura y Urbanism

Analysis of the finite difference time domain technique to solve the Schrödinger equation for quantum devices

An extension of the finite difference time domain is applied to solve the Schrödinger equation. A systematic analysis of stability and convergence of this technique is carried out in this article. The numerical scheme used to solve the Schrödinger equation differs from the scheme found in electromagnetics. Also, the unit cell employed to model quantum devices is different from the Yee cell used by the electrical engineering community. A bound for the time step is derived to ensure stability. Several numerical experiments in quantum structures demonstrate the accuracy of a second order, comparable to the analysis of electromagnetic devices with the Yee cell.a!Electronic mail: [email protected] b!Electronic mail: [email protected] c!Electronic mail: [email protected] d!Electronic mail: [email protected]

Real Time Leak Isolation in Pipelines Based on a Time Delay Neural Network

In this paper, the one leak isolation problem in a water pipeline is tackled using a Time Delay Neural Network. This scheme comes as an alternative to achieve better computing performance since the classical model-based methods usually have high workloads due to the pipe mathematical model complexity compared with the leak dynamics speed. The Neural Network structure could have better time performance exploiting the parallel architecture of some electronics devices like an FPGA. The authors propose a scheme where, due to the difficulty in obtaining training data from a real pipeline, a mathematical model is used to generate synthetic training data. Such training data is obtained using different leak magnitudes and leak positions and it is also corrupted by random noise in order to emulate real data pipe. Finally, to show the potentiality of this method, some results are presented by using real-noisy databases coming from a pipeline prototype.Following the classical leak diagnosis hypothesis, only flow and pressure sensor at both ends of the aqueducts are used for the treatment.ITESO, A.C